Single photon-counting imaging system and method thereof

Abstract

A single-photon counting imaging system and method includes an optical filter, first and second lenses, a digital micro-mirror device (DMD) control system, a single-photon counter and a data processing unit. The DMD and first and second lenses convert two-dimensional image data into a one-dimensional sequence. The ultra-weak light is filtered by the optical filter, after which the ultra-weak light image onto the DMD through the first lens. The DMD controls the probability of the photons reflected to the second lens and the second lens controls focusing of the photons. The data processing unit and single-photon counter complete sparse reconstruction. The data processing unit converts the number of photons counted by the single-photon counter within a certain period of time into the probability of detected photon counts. A photon density image is reconstructed by adopting an optimization algorithm based on the measurement matrix on the DMD and the measured value.

Description

FIELD OF THE INVENTION[0001]The invention relates to the technical field of ultra-weak light detection, in particular to a single-photon counting imaging system and a single-photon counting imaging method. High-quality two-dimensional imaging of an ultra-weak light object can be realized using a point detector by adopting the compressed sensing theory and the digital light processing (DLP) technology.BACKGROUND OF THE INVENTION[0002]Common imaging device acquires an image by recording the light intensity and the position of a certain point on an observation object. When the light intensity of the observation object is attenuated to a certain extent and reaches a single-photon level, discrete pulse signals are formed. A single photon, as an ultra-weak light, is regarded as the indivisible minimum energy unit of light, the detectable limit as well. The single-photon detection technology is applied in the fields of biological self-illumination, medical diagnosis, nondestructive materia...

AI Technical Summary

Benefits of technology

[0019]the combination of the DMD, the first lens 1 and the second lens 2 is used for converting two-dimensional image data into a one-dimensional data sequence so as to complete compressive sampling of the signals to be measured, i.e., firstly the stray light in an ultra-weak light is filtered by the light filter, and then the ultra-weak light is imaged at the DMD control system through the first lens 1, and the DMD control system controls the probability that photons are reflected to the second lens 2 and the second lens 2 controls the focusing of the photons; and

[0021]As an improvement of the technical solution, a light attenuator is also arranged on the light path from a focusing position of the second lens 2 to the single-photon counter, for attenuating the light to the working range of the single-photon detector. The light attenuator is arranged for preventing saturation caused by over high density of the measured photons and over long gating time of the single-photon counter.

[0025]the stray light in the ultra-weak light is filtered by a light filter, after which the ultra-weak light is imaged at the DMD control system through the first lens 1, and the DMD control system controls the probability that the photons are reflected to the second lens 2 and the second lens 2 controls the focusing of the photons; and

[0046]The invention has the advantages that the imaging problem of high detection sensitivity realized by using point detectors is solved by combining the compressed sensing (CS for short) theory and the digital light processing (DLP for short), with the sensitivity of the detector being on the single-photon level, the resolution being directly relevant to the DMD control system-the DMD control system having a very high resolution at present. The invention can be widely applied in the fields of biological self-illumination, medical diagnosis, nondestructive material analysis, astronomical observation, national defense and military, spectral measurement, quantum electronics and the like.

[0047]Based on the compressed sensing (CS) theory, a single-photon point detector used as a detection element, the present invention realizes two-dimensional imaging of ultra-weak light by using a single-photon counter, so the structure of the present invention is simple and its sensitivity can reach single-photon level, moreover its resolution is directly relevant to the DMD control system-the DMD control system having a very high resolution at present, therefore the contradiction between the low sensitivity, small array scale and relatively narrow wavelength range of the detector and strong demand of two-dimensional imaging of ultra-weak light object is solved.

Problems solved by technology

However, the array detector for the single-photon detection level is expensive and can be realized in only a few wave bands, and furthermore it has weak sensitivity, and so there exists the contradiction between technical immaturity and strong demand of two-dimensional imaging of an ultra-weak light object.

Images